Multipole circuit breaker

ABSTRACT

In the embodiment described, three trip-free single-pole circuit breakers magnetically responsive to overload are joined side by side, adjacent sidewalls of the breaker casings being provided with windows for swinging transfer rods. Each breaker has a toggle mechanism with a normally locked catch which on tripping of its armature opens the movable contact. The breakers have identical transfer trip cranks pivoted thereon, each trip crank having a contact bar, a trip leg and a trip transfer bar. The bars and the tube extend transversely of the swinging plane of the movable contact. The transfer trip cranks are connected by a transfer rod inserted in the transfer bars and passing to an adjacent breaker through the casing windows. The contact arm of an overloaded breaker hits its contact bar, its connector bars swing about the crank pivots and the trip legs of the other cranks release the catches of the as yet closed breakers causing their toggles to collapse and their contacts to open.

United States Patent Brackett, Sr.

[ Feb. 29, 1972 [54] MULTIPOLE CIRCUIT BREAKER [72] Inventor: Lawrence W. Brackett, Sr., Georgetown,

Mass.

[73] Assignee: Wood Electric Corporation, Danvers,

Mass.

[221 Filed: June s {1970 [21] Appl. No.: 43,737

Primary ExaminerHarold Broome Attorney-Roberts, Cushman & Grover [5 7] ABSTRACT In the embodiment described, three trip-free single-pole circuit breakers magnetically responsive to overload are joined side by side, adjacent sidewalls of the breaker casings being provided with windows for swinging transfer rods. Each breaker has a toggle mechanism with a normally locked catch which on tripping of its armature opens the movable contact. The breakers have identical transfer trip cranks pivoted thereon, each trip crank having a contact bar, a trip leg and a trip transfer bar. The bars and the tube extend transversely of the swinging plane of the movable contact. The transfer trip cranks are connected by a transfer rod inserted in the transfer bars and passing to an adjacent breaker through the casing windows.

The contact arm of an overloaded breaker hits its contact bar, its connector bars swing about the crank pivots and the trip legs of the other cranks release the catches of the as yet closed breakers causing their toggles to collapse and their contacts to open.

5 Claims, 12 Drawing Figures MULTIPOLE CIRCUIT BREAKER BACKGROUND OF THE INVENTION The field of the invention is that of electromagnetically actuated switches, specifically automatic multipole or polyphase circuitinterrupting devices with individual latch or trip means in each leg (Class 335-9).

DESCRIPTION OF THE PRIOR ART Various multipolecircuit breakers of the above type, with cross tripping of all legs if one leg is overloaded, have'been proposed. The individual circuit breakers to be correlated in this manner offer, for cross connection, several components which move on tripping, capable of transferring their motion. Such components are armature portions, toggle levers or links, toggle .latches, and moving contacts. Cross connections between any two of these components of respective breakers havebeenproposed. Most'frequently, breaker actions involving armature portions within the train of tripping force transferhave beenproposed, but their inclusion is not always advantageous. Transfer of tripping forces between opening trippedcontacts and toggle latches have been proposed, such as in U.S. Pat. Nos. 3,329,912, 3,421,129 and 3,426,30l. The present inventionis of this type.

SUMMARY OF THE INVENTION According to theinvention, each one of a plurality of circuit breakers has a.manual actuating means with release means (such as a toggle movement with a normally locked latch), overload responsive means (such as a magnet), contact means opening upon'cunlocking of the release means, and trip crank means pivoted on the breaker support. Each individual trip crank means has force receptive means (such as a contact bar):adjacent1to the movable'contact means, forceexerting means (such as a trip leg) adjacent the release means, and force transfer means for transferring'motion from an initially tripped crank'to an adjacent'crank, transversely of individual breakercasingsaln a preferred embodiment,.the tripcrank turns on thearmature pin andhas two halves one on each side of'the breaker and each having-acontact leg and a connector leg with-the pivot means therebetween. One crank half has in addition a trip leg extending towards and capable of engaging anactuating portionof the toggle locking-latch. The contact legsare joined by.a contact banextending adjacent the movable contact, and'the connector legs are joined by a connector bar. In one. embodiment, the connector bars are tubular to confine a transfer rod linking'adjacent breakers. In another embodiment, the connectorlegs and bar are omitted-and the transferrod is-received-by perforated contact bars. When the breakers are closed, the'contact bars are closely adjacent to the arms of the closed movable contact, and the trip legs are closely adjacent to the unlockingmeans of the toggle locks. When the contactarm-of an overloaded breaker opens, it hits its contactbar and the-individual trip cranks which are interconnected by.the transfer rod rotate on their pivots. The as yet nontripped toggles are unlocked opening their contacts.

Objects attained :by the above, and other characteristic aspects of the invention are among others, to provide a rugged, completely reliable multipole circuit breaker which utilizes for its cross connections uncomplicated and inexpensive components, which is economical inmanufacture and assembly, and which employs casings which can .also be used for individually mounted single-pole breakers.

BRIEF DESCRIPTION OF THE DRAWINGSv FIG. 1 is the top view of a triple-pole circuitbreaker according to the invention;

FIG. 2 is a section on-lines 22 ofFIG. 1;

FIG 3' is an elevation of oneshell with a closed circuit breaker therein;

FIG. 4 is a front view and FIG. 5 a side elevationof the trip crank according -to the invention;

FIG. 6 is an isometric view of'the trip crank;

FIG. 7 is a side elevation, similar to FIG. 5, of a modified trip crank;

FIG. 8 is an elevation similar to FIG. 3 indicating the positions of attracted armature, opening contact, and toggle'lock.

DESCRIPTION OF PREFERRED EMBODIMENTS In the present description, the complete multipole circuit.

breaker will be referred to for short as breaker unit or simply unit, whereas each individual single-pole switch will be referred to as single breaker or simply breaker. Each of the two or more breakers of a unit is or at least can be of identical construction, their interrelation being accomplished byelements whose configuration is independent of the construction,

whether or not convention, of each breaker. The single breakers will now be described by describing one of them with. reference to FIGS. 2 and 3, so far as necessary for an understanding of the present invention.

As shown in FIGS. 1 and 2, each breaker casing consists of two shells 11 and 12 which are held together by rivets 115. As

indicated in FIG. 8, the casings can be molded withan extension for an auxiliary switch serving the complete breaker unit. Referring to FIGS. 2 and 3, the circuitbreakermechanism-is mounted on a frame 31 with two parallel sideplates 32 and 33, a web 34 and a magnet support 35. The plates have holes for the pivot pins, and several projections with restraining faces held by appropriate faces of the shells. This mounting system, which is subject matter of the above copending application, is

not described herein as unessentialwith regard to the present invention, whichwill be described in detail hereinbelow. The handle 41 is pivoted on. pin 42 in the sideplates and fits semicircular recesses of respective shells. A toggle mechanism has an operator. link 45and a double-walled contactlink 46;-

The operator link 45 is pivoted on the handle at 47 andthe contact link is pivoted to the movable contact arm 49 at 52.

The movable contact arm 49 rotates on pin 53 and carriescontact 51. The two links are joined by a pivot pin 48 and a toggle trigger catch pin 60 which includes a so-called halfmoon catch with a flat 65. This catch pin 60 is pivoted on the two walls of contact link 46 and associated with a toggle lock.

crank 61 and a tripping pin 62, compare FIGS. 9 and 10. The' operator link 45 has a latch tooth 67 between the two walls of the contact link 46 (FIG. 5). An armature 70 pivoted on arma ture pin 75 has an actuator 71 at the magnet, and a leg 72 ad-' jacent the toggle trigger pin 62. Appropriate springs, described in the above-mentioned U.S. Pat. No. 3,329,912, keep the several armature, toggle and trigger elements with proper bias in the positions described and shown. With the' switch in closed position and the movable contact 51 resting on the fixed-contact 50 as shown in FIG. 3, the latchtooth 67 engages the convex region of the catch pin 60'at the edge 65.1 of the half-moon catch. The toggle is thenlocked in the position of FIG; 3; When the actuator 71 of the armature 70 turns on its pivot 75 towards the solenoid (FIG. 8), the armature leg 72 (FIG. 3) touches the pin 62, rotates the crank 61 and with it the catch pin 60 with its flat 65, releasing the tooth 67..The

locking connection between the contact link 46 and the operator link is now open, the toggle collapses as shown in FIG. 8, and the biasing springs quickly break contact at 50 and.

If it is attempted to close the circuit breaker by turning the handle after the toggle'linkage is triggered by a persistent abnormal condition, and assuming the position of FIG. 8, the two links 45 and 46 will rotate relatively to each other but the con-r tacts will remain openand the handle will move back into. open position. This is commonly referred to as trip-free operation. It should be noted that the armature actuator 71 remains in the full line position of FIG. 8 only so long as current is still flowing in the solenoid. Upon current interruption the armature returns to the position of FIG. 3, shown in dot and dash lines in FIG. 8.

For manually breaking contact the handle is rotated counterclockwise with reference to FIG. 3 and this moves the two links 45 and 46, which remain rigidly joined at 60, towards the right of FIG. 3 thus moving the contact 51 into open position by rotation on its pivot 53.

The invention proper will now be described. As shown, each breaker has a trip crank 100 which is at 100.1 pivoted in the breaker frame on the armature pin 75. The crank 100 has two contact legs 101, 102, one on each side of the breaker. These legs are firmly connected by a contact bar 105 which, as shown in FIGS. 2 and 3 is distanced from the contact arm 49 when the contacts 50 and 51 are closed. For purposes of one embodiment of the invention, the contact bar 105 is tubularly perforated as shown at 106 to receive a transfer rod. On the other side of the pivot 100.1 the crank 100 has two connector legs 108, 109 which are firmly joined by a connector bar 111 which is tubular similarly to bar 105, as indicated at 112. On that side of the trip crank 100 which is adjacent to the toggle locking mechanism with crank 61 and pin 62, the crank has a trip leg 115 which reaches near the pin 62 but does not touch it when the contacts are closed as shown in FIG. 3. A spring 118 biases the trip crank to its normal position as in FIG. 3.

The trip cranks 100 are connected by a transfer rod 120 which is inserted into the perforations 112. Only one such rod 120 is needed regardless of the number of individual breakers.

The three breakers herein shown to constitute the complete unit, namely breakers B1, B2 and B3 are each joined with .rivets 151, 152 as indicated in FIG. 2, through holes 115.1,

115.2, 116.1 and 116.2 (FIG. 12). For assembling the unit, the appropriate knockouts M3 or M4 of the casing shells (FIG. 12) are removed as indicated in FIG. 11 at N1 for breaker B1, at N2.l and N2.2 for breaker B2, and at N3 for breaker B3. Each breaker is assembled completely, with each trip crank in the same position, either all closed or all open. The transfer rod 120 is then inserted in the through hole 1 12 of the connector bar 111 of the middle breaker B2, with both ends sticking out. The rod is then inserted into the connector bars of the two outer breakers B1 and B3 until the adjacent shells touch. The unit is then completed by joining the three breakers with rivets 151, 152 through holes M1 and M2 (FIGS. 2 and 12). If the contact bar 105 is utilized as connector bar and provided with holes 106, the transfer rod 120 is mounted in similar manner.

For purposes of the present invention, the handles 41 are preferably interconnected by means of spacers 41.1 held by a rivet 42.2 in appropriate holes of the handle 41, as indicated in FIG. 2.

While the above described embodiment has three singlepole breakers, it will be understood that two, or more than three, single breakers can be associated in this manner. The transfer rod 120 is inserted into the perforations of connector bars 111 or contact bars 105 analogously to the manner described above for the triple-pole circuit breaker.

The operation of the above-described multipole circuit breaker is as follows.

With all contacts closed as indicated in FIG. 3, the contact bars are distanced from their corresponding contact arms 49, and the trip legs are distanced from the corresponding lock tripping pins 62 of the toggle locks 60. The transfer rod reaches through the shell knockouts of adjacent breakers, as indicated in FIGS. 1, 2 and 11.

When one of the breakers becomes overloaded, its opening contact arm 49 hits its contact bar 105 and this causes all trip cranks, connected by the transfer rod 120, to rotate on pivots 100.1. The trip legs 115 thereupon hit their tripping pins 62 and the as yet closed breaker or breakers open as shown in FIG. 8. It should be noted that the armature actuator 71 is in the full line position of FIG. 8 only so long as current flows through contacts 50 and 51 as indicated in dot and dash. With the breakers fully open, all armatures are in the dot and dash position of 71 of F IG. 8 and all movable contacts 51 are in the full line, open position.

It will be noted that, as initially mentioned, no portions of the armatures are ever in transfer force transmitting relation with any part of the present multipole trip crank construction.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A multipole circuit breaker unit assembled from a plurality of substantially identical single pole circuit breakers each including a frame with pin means for mounting a movable contact means, a means for manually actuating said contact means having normally locked release means, an overload responsive means for automatically moving said contact means to open it by unlocking said release means and a trip crank means, said trip crank means including two contact legs one on each side of the actuating means,

the contact legs being connected by a contact bar extending adjacent and operable by said contact means, and the contact legs having pivot holes receiving one of said pin means for rotation of the contact bar thereon, and

a trip leg fast to one of said contact legs for rotation with said contact bar and extending adjacent and capable of actuating said release means; and

force transfer means interconnecting said trip crank means of the single-pole circuit breakers;

whereby upon overload on one of the breakers opening its contact means, said contact bar is displaced by the opening contact means thereby rotating all trip crank means with the trip legs of the nonoverload breakers impinging on their release means and opening their contact means.

2. Circuit breaker unit according to claim 1, further comprising two connector legs extending from the contact legs beyond said pivot hole which is located between each connector leg and contact leg, and a perforated connector bar fast at each end to a respective connector leg.

3. Circuit breaker according to claim 3 further comprising a transfer rod extending through the perforations of said connector bars.

4. Circuit breaker according to claim 1 wherein said contact bars are perforated.

5. Circuit breaker according to claim 4 further comprising a transfer rod extending through said perforations of the contact bars. 

1. A multipole circuit breaker unit assembled from a plurality of substantially identical single pole circuit breakers each including a frame with pin means for mounting a movable contact means, a means for manually actuating said contact means having normally locked release means, an overload responsive means for automatically moving said contact means to open it by unlocking said release means and a trip crank means, said trip crank means including two contact legs one on each side of the actuating means, the contact legs being connected by a contact bar extending adjacent and operable by said contact means, and the contact legs having pivot holes receiving one of said pin means for rotation of the contact bar thereon, and a trip leg fast to one of said contact legs for rotation with said contact bar and extending adjacent and capable of actuating said release means; and force transfer means interconnecting said trip crank means of the single-pole circuit breakers; whereby upon overload on one of the breakers opening its contact means, said contact bar is displaced by the opening contact means thereby rotating all trip crank means with the trip legs of the nonoverload breakers impinging on their release means and opening their contact means.
 2. Circuit breaker unit according to claim 1, further comprising two connector legs extending from the contact legs beyond said pivot hole which is located between each connector leg and contact leg, and a perforated connector bar fast at each end to a respective connector leg.
 3. Circuit breaker according to claim 3 furtHer comprising a transfer rod extending through the perforations of said connector bars.
 4. Circuit breaker according to claim 1 wherein said contact bars are perforated.
 5. Circuit breaker according to claim 4 further comprising a transfer rod extending through said perforations of the contact bars. 